Revealing Holocene ice-ocean-biota relationships with sedimentary ancient DNA metagenomics in Melville Bay, North-West Greenland

Qimusseriarsuaq (Melville Bay) is a marine nature reserve and wildlife sanctuary located in North-West Greenland, which is particularly vulnerable to anthropogenic climate change. Due to high ice mass loss of the Greenland Ice Sheet, glacier retreat, increased freshwater input, and sea ice decline in this area, it is a critical yet understudied Arctic region, particularly regarding the impacts on the marine food webs. To fill this gap, we investigate the marine sedimentary record from the Holocene Thermal Maximum (HTM) as an analog for warming scenarios projected for the 21st century.
We present metagenomic data of sedimentary ancient DNA from marine sediment core LK21-IC-st26, which was collected during the ICAROS expedition 2021 onboard HDMS Lauge Koch. Laminations at the base of this 320 cm long core indicate its location close to an ancient ice shelf and thus highlights that our core captured the full Holocene since the deglaciation (past ~11.7 ka).
Focusing on eukaryotes and primary producers, we will show composition and diversity changes following the deglaciation into the HTM and the Late Holocene. We thereby provide novel insights into ecological transformations driven by ice dynamics, ocean circulation changes, and climate variability of North-West Greenland. By exploring the fingerprints of these past processes, this study will advance our understanding of Arctic marine ecosystem dynamics and ultimately will inform predictions for future changes in the region.